Possessing a state of pseudo-equilibrium that has a free energy higher than that of the true equilibrium state but from which a system does not change spontaneously
(1) nonequilibrium state of a material with respect to some transition, conversion, or reaction but stabilized kinetically either by rapid cooling or by some molecular characteristics; (2) possessing a state of pseudoequilibrium that has a free energy higher than that of the true equilibrium state
A classical system is metastable if it is above its minimum-energy state, but requires an energy input before it can reach a lower-energy state; accordingly, a metastable system can act like a °stable system, provided that energy inputs (e g , thermal fluctuations) remain below some threshold Systems with strong metastability are commonly described as stable Quantum mechanical effects can permit metastable states to reach lower energies by tunneling, without an energy input; an associated, broader definition of metastable embraces all systems that have a long lifetime (by some standard) in a state above the minimum-energy state
An indeterminate state for a logical system Typically occurs when sample and hold times are not adhered to in devices such as a Bistable and the logic hovers in a transient state for an indeterminate time One of the causes of random failures in digital systems - any asynchronous external event can not with certainty be sampled without the possibility of a Metastable state